1,206 research outputs found
Get rid of inline assembly through verification-oriented lifting
Formal methods for software development have made great strides in the last
two decades, to the point that their application in safety-critical embedded
software is an undeniable success. Their extension to non-critical software is
one of the notable forthcoming challenges. For example, C programmers regularly
use inline assembly for low-level optimizations and system primitives. This
usually results in driving state-of-the-art formal analyzers developed for C
ineffective. We thus propose TInA, an automated, generic, trustable and
verification-oriented lifting technique turning inline assembly into
semantically equivalent C code, in order to take advantage of existing C
analyzers. Extensive experiments on real-world C code with inline assembly
(including GMP and ffmpeg) show the feasibility and benefits of TInA
Interface Compliance of Inline Assembly: Automatically Check, Patch and Refine
Inline assembly is still a common practice in low-level C programming,
typically for efficiency reasons or for accessing specific hardware resources.
Such embedded assembly codes in the GNU syntax (supported by major compilers
such as GCC, Clang and ICC) have an interface specifying how the assembly codes
interact with the C environment. For simplicity reasons, the compiler treats
GNU inline assembly codes as blackboxes and relies only on their interface to
correctly glue them into the compiled C code. Therefore, the adequacy between
the assembly chunk and its interface (named compliance) is of primary
importance, as such compliance issues can lead to subtle and hard-to-find bugs.
We propose RUSTInA, the first automated technique for formally checking inline
assembly compliance, with the extra ability to propose (proven) patches and
(optimization) refinements in certain cases. RUSTInA is based on an original
formalization of the inline assembly compliance problem together with novel
dedicated algorithms. Our prototype has been evaluated on 202 Debian packages
with inline assembly (2656 chunks), finding 2183 issues in 85 packages -- 986
significant issues in 54 packages (including major projects such as ffmpeg or
ALSA), and proposing patches for 92% of them. Currently, 38 patches have
already been accepted (solving 156 significant issues), with positive feedback
from development teams
Goal-Oriented Mutation Testing with Focal Methods
Mutation testing is the state-of-the-art technique for assessing the
fault-detection capacity of a test suite. Unfortunately, mutation testing
consumes enormous computing resources because it runs the whole test suite for
each and every injected mutant. In this paper we explore fine-grained
traceability links at method level (named focal methods), to reduce the
execution time of mutation testing and to verify the quality of the test cases
for each individual method, instead of the usually verified overall test suite
quality. Validation of our approach on the open source Apache Ant project shows
a speed-up of 573.5x for the mutants located in focal methods with a quality
score of 80%.Comment: A-TEST 201
Modified perturbation theory approach for tt-bar production and decay
The modified perturbation theory (MPT), based on direct expansion of
probabilities instead of amplitudes, allows one to avoid divergences in the
phase-space integrals resulting from production and decay of unstable
particles. In the present paper the range of applicability of MPT is determined
numerically in the case of the process . It is shown that with the complete expansion in powers of
the coupling constant (without Dyson resummation) MPT operates best at the
energies located near the maximum of the cross-section and slightly above the
maximum. In this region the MPT expansion within the next-to-leading order
considerably exceeds in accuracy well-known DPA approach.Comment: LaTeX, 11 pages, 3 eps figure
Burkitt lymphoma: Trends in children below 15 years reveal priority areas for early diagnosis activities in north-west Cameroon
Background: Burkitt lymphoma is one of the most common childhood cancers in Cameroon. Incidence rates of 5.9/100 000 and 2.58 per 100 000 have been reported in two studies in 2005 and 2012 amongst children below 15 years in the North-West Region.
Aim: This study seeks to examine how Burkitt lymphoma incidence has varied between the various health districts of north-west Cameroon from 2003 to 2015.
Setting: North-West region of Cameroon.
Method: Ethics approval was obtained from the relevant university and Health Services Institutional Review Board. Population data was obtained from the regional delegation of public health. The Paediatric Oncology Networked Database registry from two hospitals and two pathology-based registries were reviewed for cases per year from the various districts. Age-standardised incidence rates were computed for all districts by year using the World Health Organizaion world standard populations.
Results: A total of 317 cases were registered. Overall age-standardised incidence rate was 3.07 per 100 000. Annual incidence ranged from 0.09 in 2003 to 6.12 in 2010. The districts with the highest incidence rates for the entire study period include Nwa with 10.54; Ndop with 5.63; Benakuma with 5.48; Ako with 4.97; and Nkambe with 4.73.
Conclusion: Clustering of Burkitt lymphoma is seen in the region, with the highest incidence in Nwa, Ndop, Benakuma, Ako and Nkambe. These districts should be prioritised for awareness creation campaigns. There is need for a population-based childhood cancer registry in the region, which will use both active and passive surveillance methods to record all childhood cancer cases
Final State Interaction Effects in the Process near Threshold
We use the Paris nucleon-antinucleon optical potential for explanation of
experimental data in the process near threshold. It is
shown that the cross section and the electromagnetic form factors are very
sensitive to the parameters of the potential. It turns out that final-state
interaction due to slightly modified absorptive part of the potential allows us
to reproduce available experimental data. We also demonstrated that the cross
section in channel is larger than that in one, and their
ratio is almost energy independent up to 2.2 GeV.Comment: references added, changes in the text according to referee comment
Low-Mass Baryon-Antibaryon Enhancements in B Decays
The nature of low-mass baryon-antibaryon enhancements seen in B decays is
explored. Three possibilities include (i) states near threshold as found in a
model by Nambu and Jona-Lasinio, (ii) isoscalar states with coupled to a pair of gluons, and (iii) low-mass enhancements favored by the
fragmentation process. Ways of distinguishing these mechanisms using angular
distributions and flavor symmetry are proposed.Comment: 8 pages, LaTeX, no figures, to be submitted to Phys. Rev. D. One
reference adde
Highly sensitive multipoint real-time kinetic detection of Surface Plasmon bioanalytes with custom CMOS cameras
Phase sensitive Surface Plasmon Resonance (SPR) techniques are a popular means of characterizing biomolecular interactions. However, limitations due to the narrow dynamic range and difficulty in adapting the method for multi-point sensing have restricted its range of applications. This paper presents a compact phase sensitive SPR technology using a custom CMOS camera. The system is exceptionally versatile enabling one to trade dynamic range for sensitivity without altering the optical system. We present results showing sensitivity over the array of better than 10−6 Refractive Index Units (RIU) over a refractive index range of 2×10−2 RIU, with peak sensitivity of 3×10−7 RIU at the center of this range. We also explain how simply altering the settings of polarization components can give sensitivity on the order of 10−8 RIU albeit at the cost of lower dynamic range. The consistent response of the custom CMOS camera in the system also allowed us to demonstrate precise quantitative detection of two Fibrinogen antibody–protein binding sites. Moreover, we use the system to determine reaction kinetics and argue how the multipoint detection gives useful insight into the molecular binding mechanisms
The spindle position checkpoint is coordinated by the Elm1 kinase
Localization and activation of Elm1 at the bud neck coordinates SPC activity with mother–daughter polarity during cell division
Induced pseudoscalar coupling of the proton weak interaction
The induced pseudoscalar coupling is the least well known of the weak
coupling constants of the proton's charged--current interaction. Its size is
dictated by chiral symmetry arguments, and its measurement represents an
important test of quantum chromodynamics at low energies. During the past
decade a large body of new data relevant to the coupling has been
accumulated. This data includes measurements of radiative and non radiative
muon capture on targets ranging from hydrogen and few--nucleon systems to
complex nuclei. Herein the authors review the theoretical underpinnings of
, the experimental studies of , and the procedures and uncertainties
in extracting the coupling from data. Current puzzles are highlighted and
future opportunities are discussed.Comment: 58 pages, Latex, Revtex4, prepared for Reviews of Modern Physic
- …